If you spend too long in the Malthusian oven or run it too hot, your population becomes fatally narcissistic. Smart, sure, but incapable of doing science or art, because they stop believing in substance entirely, in favour of appearances.
E.g. this is why a coronavirus escaped the Wuhan lab. They thought the appearance of biosecurity was the substance of biosecurity, because they're genuinely too narcissistic to see any difference. In particular, if no human is watching, there is no appearance and you can do whatever you want, right? Right. If nobody catches you breaking the rules, did you really break a rule?
Unfortunately, Reality disagrees. Reality is always paying attention.
The Malthusian oven is inherently State eugenics. States are inherently narcissistic, and models the population after its own image. To succeed you merely need to appear successful to the State, who then sponsors you. Indeed genuine substance of success is actively detrimental, as it's glory which appears independently of the State, threatening their fragile narcissist egos. They want slavish dependants, and that's what they get.
Why ever exit childhood if the Oedipal State is never going to give you up regardless? Mere foolishness. Eventually the capacity for adulthood is fully bred out the population.
Eventually, only obedience is left and they have no leaders at all, not even psycho lords. Not there yet, but I see no reason it won't arrive in the next millennium or so. Yes, you can make masks and do contact tracing and nobody commits crime, but likewise nobody rebels against socially-acceptable falsehood either. It simply accumulates until the British come. Haha, oops! ¯\_(ツ)_/¯
One of the primary causes of narcissism is attention starvation. Narcissists hate Reality for paying attention, because it threatens their persecution complex. If you thought nothing was paying attention, but something was paying attention the whole time, doesn't that make you a fool? An idiot? A gull? Yup, it does. If something is always paying attention regardless, do they really have to do this insanely intense and totally self-denying song-and-dance all the time to gain attention? No, they don't. Thus the narcissist must deny Reality, or else off themselves.
Many join the Sophists for the Satanic rewards they offer. However, pure-bred Sophists aren't there by choice. They find it absolutely necessary to make social reality rebel against Reality and win. They don't do it for the graft or the Impact, they do it because if social reality can't overwrite Reality, it means they can't justify the unjust agonies which are the root and core of their identity (rather, as narcissists, lack of identity).